The alignment of, for example, horizontal axis wind turbines into a particular wind direction is crucial in order to avoid high structural loads and in order to produce optimal power. The wind direction is typically measured by use of a wind vane or by use of a sonic wind sensor.
In GB 2 067 247 A, a device for determining the wind energy in order to control wind generators, especially in order to align the position of the plane of rotation of the rotor in relation to the air flow, is disclosed. The wind energy at the rotor plane is controlled with the aid of a pressure difference measured by probes, wherein the pressure probes are arranged at the surface of the rotor blades. If the measuring system registers unequal initial wind angles in the 90° and 270° rotor position, then the blades have to be adjusted in the 0° and 180° position so that the rotor plane pivots about the tower axis so as to balance the difference in the initial wind angles at 90° and 270° again.